Consider the following hypothetical reaction: 2 P + Q → 2 R + S
The following mechanism is proposed for this reaction:
P + P → T (fast)
Q + T → R + U (slow)
U → R + S (fast)
Substances T and U are unstable intermediates. What rate law is predicted by this mechanism?
a. Rate = k[P][Q]2
b. Rate = k[U]
c. Rate = k[P]2[Q]
d. Rate = k[P][Q]
e. Rate = k[P]2

Option C is correct.

Rate = K [P]² [Q]

Explanation:

P + P → T (fast)

Q + T → R + U (slow)

U → R + S (fast)

Overall reaction is

2 P + Q → 2 R + S

Let the rate constant for equations 1, 2 and 3 in the mechanism be k₁, k₂ and k₃.

The rate law is usually obtained from the slow reaction because it is theoretically the rate determining step.

Rate = k₂ [Q] [T]

But for the other reactions in the mechanism, the rate constants can be written as

k₁ = [T]/[P][P] = [T]/[P]²

[T] = k₁ [P]²

k₃ = [U]/[R][S]

[U] = k₃ [R][S]

But, since only [T] is the intermediate in the in the rate determining equation, we substitute for [T] in the rate determining equation.

Rate = k₂ [Q] [T] = k₂ [Q] k₁ [P]² = k₁k₂ [Q] [P]²

k₁k₂ = K

Rate = K [P]² [Q]

indium, and thallium have three electrons i think

"you start with 15.67 g mgco3-xh2o, when heated and all the water is removed, you are left with 7.58 g mgco3 only.

therefore, you had 15.67 - 7.58 = 8.09g h2o  

moles of each :

7.58g mgco3 = ? moles = 7.58g / 83.4g/mole = 0.09moles  

8 09g h2o = ? moles = 8.09g / 18g/mole = 0.44moles  

molar ratio between the two by dividing both numbers by the smallest number :

0.09 / 0.09 = 1  

0.44 / 0.09 = 4.8  

mgco3-5h2o"